Question on construction / wood working ?

Question on construction
I have seen a few posts on chimneys recently in this group.
What is the general rule on chimneys in terms of height ?
How much higher than the roof do they have to be ?
Can they be in line with the roof ?
Is there a law on this ? especially in N. California ?
Thanks
Jessica

I can't speak about the laws of the state of California, but there is a
law of physics that you will regret ignoring. The chimney must be
several feet (I'd say at least 2) higher than the highest point of the
roof. The reason is that when the wind blows, the air "stacks up" on
the upwind side of the roof, creating a high pressure region there. If
your chimney is lower than the peak, certain wind conditions will force
smoke back down the chimney. Ever wonder why old factories had such
tall smokestacks? In general, the taller the chimney the better it
draws.
DonkeyHody
"Even an old blind hog finds an acorn every now and then."

All the references, and my own experience, show that it needs to be at
least 2' higher than any point within 10' in order to get a proper
draft. Doesn't matter whether what's within 10' is a tree or a roof
line.

All the references, and my own experience, show that it needs to be at
least 2' higher than any point within 10' in order to get a proper
draft. Doesn't matter whether what's within 10' is a tree or a roof
line.
Yeah, I know referenced do call for that but I believe that with those specs
you are pretty much insured to have a good draft. However as with my house
and the several in the neighborhood that are built like mine the chimney is
not taller than the peak of the house. Perhaps the specs will work in "any
situation" and my set up works if the roof is like mine.

Charlie,
That also happens to be the building code in most parts of the country
(using one of the three national codes.)
Measure the highest point within 10' from the chimney, make the top 2'
higher than that.
Old guy

All the references, and my own experience, show that it needs to be at
least 2' higher than any point within 10' in order to get a proper
draft. Doesn't matter whether what's within 10' is a tree or a roof
line.

I'm trying to figure what I might have
left out to cause you to conclude this. As stated, the "topmost" or cap of the
chimney (Maybe that's it: Not the chimney per se) was to be a minimum of 10 feet
in a horizontal axis from the nearest roof plane. Sorry about the
miscommunication, I thought I was clear. Tom

Isn't the chimney right next to the nearest roof plane? :) We know what
you meant, but look at the literal translation of what you wrote.
More formally is can read:
provide a minimum of 2 feet clearance to all roof surfaces and structures
within 10 feet of the chimney and 3 feet above the highest point that the
chimney penetrates the roof (i.e. the side of the chimney furthest up the
roof slope). This is a national code, outlined in section FG503.5.4 of the
International Fuel Gas Code.

There are ground rules dictated by the laws of physics.
The 'usual case form' of which are usually included in local building codes.
That said, there _are_ ways to make a chimney work
in 'unconventional situations.
In the house I grew up in, when we remodeled and added a fireplace, the
chimney top was around 10 foot below the neighbor's roof-line (about 14
feet away), below two roof peaks on our house (8 feet, and 15 feet away),
and there was a large locust tree (estimated 20 ft taller), less than 4 feet
away.
The brick-mason _refused_ to build it, until the architect had a lengthy
discussion with him ; he *knew* -- from years of experience -- that that
fireplace would never draw right.
He would have been right, but the architect knew what he was doing, and
had already ordered, what was then called a 'draft inducer' -- a -big-
(entirely passive) 'pot' that installed on the top of the chimney, and
more than made up for the 'obstacles' surrounding the chimney. As I
recall, we _did_ have to get a 'variance' from the city allowing the
construction, since it _was_ contrary to code standard.

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